The present invention relates to devices for measuring and displaying linear or angular displacements and more particularly to scaling devices of the type adapted for use with marking instruments suitable to accurately mark various media surfaces. In particular, the present invention relates to scaling devices commonly encountered in mechanical, architectural and other such drawing pursuits which are used for the purpose of determining line and angle measurements to be applied to drafting as well as ascertaining the decimal or other equivalent of lines or angles on existing draftings or pictures.
Scaling devices presently used have remained unchanged in principal virtually since their creation. In general they are mechanical devices of various configurations but having in common a scale edge with graduations marked thereon which a user employs both for establishing the displacement of a line or angle segment to be drawn or alternatively, applies such a device to an existing drawing and after an appropriate alignment interprets the markings on the mechanical scale proximate the non-index limit thereof to determine the numerical value of the displacement of such segment. Some disadvantages associated with such scaling devices include the need for many scales of different ratios and units which are slow to use because the user must interpret the gradations by converting a fractional or decimal value into the linear displacement which is viewed on the scale. In many cases this is not easy to do because of the need for interpretation between gradations. Moreover, to ensure accuracy, the process should be repeated to confirm the user's initial conclusion. Unfortunately, the present method has attendant thereto, errors in interpretation of scale gradations by the user as well as conversion errors, mathematical errors, confirmation errors and errors in using improper scales to begin with.
The primary object of this invention is to obviate the previously described disadvantages of the prior art by enabling a user to input fractional or digital data into a distance measuring and displaying apparatus together with scale and unit conversion information as required, and to have the device display the displacement of the desired segment in clear illuminated markings of fine gradation and to confirm the length or angle by displaying the numerical value thereof in a clearly readable display.
Another object is to enable the measuring of existing displacements by having the user align the index cursor of the apparatus with one limit of the displacement to be measured and by aligning a slideable or equivalent member with the other limit of the displacement to be measured and having the apparatus display in digital form the precise value of the displacement segment being measured.
In addition to increasing the speed with which displacements can be drawn and measured, the calculating capacity of the device would perform all of the mental functions required for conversion of units and scales, enabling the operator, for example, to enter all data from metric measurements and having all displacements indicated in non-metric units. Another advantage of the invention is the incorporation of appropriate electronic calculating means to enable a user to display or measure displacements which are nonlinear. Such nonlinear displacements are encountered in perspective scaling or measurement from photographs and the like.